24. September 2017 · Comments Off on How to find Created, Published and Modified Dates for a Web Page · Categories: Web · Tags: Internet
Last updated on 04/26/2022

Finding the created, published or last modified date for web pages isn’t always as straightforward as it might appear. Although there are several ways to find the dates of web pages, none are 100% reliable, because regardless of the method used, no standard exists for dating web pages. The most authoritative way to find dates is from the page content itself, and even that has its shortcomings, since nothing requires dates to be accurate in the first place. In most cases, the best that can be achieved will be an approximation.

calender

Some of the methods that can be used to find created, published, or modified dates for web pages are:

  1. Web page content
  2. HTTP Headers
  3. Browser Plugins
  4. Javascript in Address Bar
  5. The Wayback Machine
  6. Google Cache
  7. RSS Feed

1. Web Page Content (preferred method when possible)

Pages often have a first published, updated, or posted date somewhere on the page. As mentioned, although this is the most accurate method, it still has its problems. An author could leave the date out, or use a wrong date – either intentionally or unintentionally. Even so, obtaining dates from web page content is the most accurate and authoritative method.

2. HTTP Headers

The Last-Modified field is an optional response field that reflects the date the origin server believes that the resource was modified. Because it is an optional field, it may or may not exist. Also, because no standard exists as to what the Last-Modified date field means, it’s often inaccurate or incorrect since that field also reflects any alterations made to the page, such as user comments or any changes other than the content.

3. Browser Plugins

There are browser plugins that can read a web page’s Last-Modified date field, but this method is still subject to the problems described for HTTP Headers above.

4. Javascript in Address Bar

This is a quick and easy way to retrieve the date from the site’s Last-Modifed date field in the HTTP Headers. To use it, just copy and paste the JavaScript string below to the address bar, or save it to a bookmark on your browser’s bookmark bar:

javascript:alert(document.lastModified)

Note: With dynamically generated content this will not work. Also, newer Internet browsers with an Omnibox require the user to manually type in javascript: even after they paste the entire string.

5. The Wayback Machine

The Way Back Machine was created by the nonprofit organization, the Internet Archive. It archives sites from the World Wide Web and other Internet information. There are a number of limitations to using this method including:

  • not all pages on a site may be included
  • not all sites are included. Webmasters can request that they not be included
  • often it doesn’t include all changes made to web sites
  • it may not be up-to-date. It can take several months for pages to appear
  • user-defined dates cannot be specified, but only dates crawled by the Way Back Machine’s web crawler

6. Google Cache

Google Cache displays a web page when it was last crawled by Google. There are several problems with this method including:

  • there isn’t a way to know the last time a page was crawled
  • it isn’t possible to specify a date range of the cache
  • changes to web sites are not tracked

To use Google Cache, enter the following into your web browser’s address bar, changing the name at the end of the URL to the site in question:

https://webcache.googleusercontent.com/search?q=cache:https://www.NameOfWebsite.com

7. RSS Feed

Many, but not all, sites include a RSS feed. If so, the published date for the page may be contained within its XML file. RSS XML files could have any name, but often use names such as index.xml or feed.xml. If it exists, it may be possible to view the file in a web browser to find dates. For further information, see Opening XML Files with a Browser. A simpler and easier option is to view the RSS feed for the page using a RSS feed reader.

Conclusion

If possible, the most authoritative and reliable method for finding the created, published, or modified dates is from the web page content. If dates don’t exist in the content, one or a combination of the above methods can be used to obtain approximate dates.

References:

Determine last modified date of a web page – Computer Hope

How do I find out when a web page was written? – Ask Leo

How to find out when a web page was created or updated – Maxi-Pedia

How to Know When a Web Page was Last Modified? – Infopackets

 

 

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08. December 2011 · Comments Off on Using SSH to secure Internet connections · Categories: Networking, Web · Tags: Linux, Security, Windows
Last updated on 09/23/2021

Two ways to use SSH to secure Internet connections are local port forwarding and dynamic port forwarding. Local port forwarding forwards web traffic from a server, while dynamic port forwarding transforms your SSH client into a SOCKS proxy server. Both can be useful for secure Internet access in insecure environments such as public networks. To use either, you need to be able to login onto a remote system. Both are easy to use.

Local Port Forwarding

Local port forwarding can be used to access specific sites from another machine. For example, to route traffic from www.somewebsite.com on a remote PC ([email protected]) to port 12345 on a client PC, the following could be entered into a command window:

ssh -L 12345:www.somewebsite1.com:80 [email protected]<host>

multiple connections may also be combined into one command as follows:

ssh -L 12345:www.somewebsite1.com:80 -L 23456:www.somewebsite2.com:80 [email protected]<host>

Use:
You just need to open a browser and point it to https://localhost:12345/ to securely access somewebsite1.com or https://localhost:23456/ to access somewebsite2.com.

Note: An IP address can also be used in place of yourdomain.com (e.g. [email protected]).

Dynamic Port Forwarding

Dynamic port forwarding is even more powerful as it allows you to securely connect to any web page and to bypass firewalls. To set it up, the following could be entered into a command window:

ssh -C -D 23456 [email protected]
  • The -C is optional and is used to enable compression, which can speed up connections
  • The -D enables dynamic port forwarding
  • 23456 is the port on the client PC

Use:
To use this connection, you will need to configure your browser to use a SOCKS proxy. See the following articles on how to do this for your browser:

Make Tech Easier – How to Secure Your Internet Connection via SSH

Ubuntu Help – SSHOpenSSHPortForwarding (see Dynamic Port Forwarding)

The How-to-Geek – 5 Cool Things You Can Do With an SSH Server (see SSH Tunneling)


Useful Related Articles:

Linux Magazine – Port Forwarding with SSH

OpenBSD Man Pages for SSH – Manual Pages

University of Victoria – An Introduction to the Black Art of Port Forwarding with SSH

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10. March 2011 · Comments Off on Basic Opera Tweaks and Loading Issues · Categories: Web · Tags: Web Apps
Last updated on 03/02/2024

Some basic tweaks for the Opera (ver 11.xx) browser addressing some of the most common complaints for users, with a focus on loading issues and performance.

The following links can be used to test the loading performance of Opera ver 11.xx as recommended by Opera forum users:

Check that Opera can load this page without hanging: https://www.good.is/

Check that Opera is able to load all images: Max Connections

Update 02/03/12: The following tweaks appeared to make a difference for loading problems in ver 11.xx. The following settings were tested on a Vista (32 bit) dual-core system (1.46GHz). Note: the following settings are suggestions only. Adjust as required to obtain the best performance using the two test links provided above.

  • Enter opera:config in the address bar
  • Enter “Performance” into search on the Preferences Editor page
  • Expand the Performance Section
  • Max Connections Server – Change from 16 to 6
  • Max Connections Total – Change from 64 to 16
  • Max Persistent Connections Server – Change from 6 to 4 (6 performed best on a WinXP system)
  • Network Buffer Size – Change from 128 to 64
  • Hit “Save” at bottom of the Performance Section

Source: Opera for Windows Forums

Update 5/16/11: A number of users in the Opera for Windows Forums continue to experience loading problems with ver 11.xx. Also see here and here and here. Some forum members recommend ver 10.63 (clean install to a separate folder) if experiencing problems with ver 11.xx.

Note: According to discussions at the Opera community forums, some users claim they have experienced intermittent loading issues with Opera Versions 10.50 up to version 11.10. Symptoms include incomplete loading, temporary freezing, a stuck progress bar, or loading the page headers only. The problem is more likely to occur when multiple (10-20) tabs are open; however, it should be noted that many users are not experiencing these problems. In any case, this is a topic of discussion in the Opera forums here and here and here. Restarting Opera often temporarily corrects the problem. Apparently there is no single solution and what works in one case may not work in another. Below is a list of changes that forum members have used to resolve the loading issue:

  • disable Javascript (this may also disable useful functions on some web pages)
  • perform a clean install of Opera to a separate directory
  • disable Unite
  • turn off turbo mode
  • delete the dcache4 file
  • disable or update flash
  • delete the HOSTS file or revert to an earlier version
  • change to the default skin
  • turn off fraud and malware protection

Some users have recommended using older versions from ver 10.10 or earlier. Older versions of Opera can be downloaded from Filehippo as well as from other sites.

The tweaks and troubleshooting suggestions below still apply and can help with loading issues, but won’t correct intermittent loading problems if caused by a possible bug (?) for versions 10.50 to 11.xx; however, some users suspect that the loading issues are likely caused from extra, corrupted, or obsolete files leftover from previous installations/upgrades.

Some Web Sites not Loading or Partially Loading:

This can be caused by the user-agent string setting. Changing this setting is usually the first thing to try with troublesome web sites. A good article explaining the user agent string is here. In short, most browsers, including Opera, have a user-agent string that identifies them. This allows servers to tailor content specific to particular browsers. Unfortunately, some sites limit their support to Internet Explorer or Firefox. In such cases, Opera may have trouble loading those pages. The way to get around this is to use user-agent spoofing. User agent spoofing just changes the user-agent string so that a browser is identified as supportable and thus works on that web site. Not surprisingly, by default, the user-agent string for Opera is set to Opera, but it’s easy to change it to Firefox or Internet Explorer. If your web pages are not loading, you can check your user-agent string setting here or by typing the following into the address bar: “javascript:alert(navigator.userAgent)” (without quotes). Below is an example of user-agent string spoofing that changes Opera’s identity to Firefox (click to enlarge).

opera user agent set to firefox

There are two methods to change Opera’s user-agent string: (1) site specific from the menu or a web page, and (2) limited global settings using opera:config (limited because only the first 3 of the 5 options can be set globally).

Setting site specific user-agent string from the menu or page:

Goto Menu ->Settings ->Quick Preferences ->Edit Site Preferences ->Network Tab or right-click on the web page and select Edit Site Preferences from the context menu, and then click on the Network Tab. At the bottom of the Network Tab, select one of the five user string options to use for that site and then hit OK:

  1. Identify as Opera
  2. Identify as Firefox (Opera contained in user-agent string)
  3. Identify as Internet Explorer (Opera contained in user-agent string)
  4. Mask as Firefox (no mention of Opera in user-agent string)
  5. Mask as Internet Explorer (no mention of Opera in user-agent string)

Opera Site Preferences window

Note that Opera will still be mentioned in the user-agent string for the first three options. For the last two options, Opera isn’t mentioned at all. Whether to select either “Mask as Firefox” or “Mask as Internet Explorer” is dependent on the situation. For instance, some servers may block content when any mention of Opera is in the user string. However, other servers may detect Opera even with user-agent string masking (last two settings) and request that the user-agent string be changed to reflect Opera (first three settings) before loading the page.

Set global user-agent string with opera:config (limited settings):

In Opera’s address bar type “opera:config” and hit ENTER. Type “Spoof UserAgent ID” (without quotes) into the Quick Find box on the Preferences Editor. When the User Agent option box appears, select a number corresponding to one of the first three options to set the global user-agent string. To display the choices, click the question mark next to the lower default button. Although listed, the last two user-agent settings, “Mask as Firefox” and “Mask as Internet Explorer”, cannot be applied globally. Hit the save button and close the window to save.

Note that although the five user-agent choices are identical to those in the site specific user-agent settings; however, “Mask as Firefox” and “Mask as Internet Explorer” are listed as site-specific, so that only the first three can be set globally. If either “Mask as Firefox” or “Mask as Internet Explorer” is selected anyway, that setting isn’t actually in effect and the user-agent string resets to the default with a browser restart.

Opera Preferences Editor Window

Java Causing Some Web Sites to Partially Load or Freeze:

This may be caused by a problem with the Java Runtime Environment (JRE), including corrupted, out-of-date, or multiple installations. You can check to see if you have the latest version of the JRE installed here.

Close all browsers and remove all older versions of the JRE using add/remove programs in Control Panel, or with another tool such as JavaRa, which is an open-source and easy-to-use tool especially designed for cleaning up the JRE. However, use caution with the additional tasks options as some can disable Java or prevent it from being updated. The Remove Older Versions feature on the main window can be safely used.

JavaRa Window

javara additional options

Java can be enabled or disabled using the Preferences Editor. Enter “opera:config” (without quotes) into the address bar, and then enter “java” (without quotes) into the Quick Find box of the Preferences Editor to bring up the Java settings box. In the Java settings box, a check enables Java and unchecking it disables Java. Click the Save button and restart Opera. Recheck to see if the change enables page loading.

java enable disable window

If you see  the “jusched.exe” error, this can affect page loading.  Jusched.exe is the Java updater. The updater can be disabled in Control Panel in WinXP. With Opera closed, goto Start ->Settings ->Control Panel and double-click the Java icon. In the Java window, click the Update Tab and uncheck “Check for Updates Automatically”. Hit OK to save. Start Opera and check page loading. Note that if  the Java updater is disabled, it will be necessary to manually check for Java updates from time to time.

Java Updater Window

Plug-ins, Widgets or Extensions causing Loading Problems:

Widgets

To quickly check if a widget is causing loading problems, goto Menu ->Widgets ->Manage Widgets and delete all the installed widgets displayed in the left panel. Close and restart Opera to check loading. Of course, you can also delete them one-at-a-time instead.

Extensions

To quickly check if an Extension is causing loading problems, goto Menu ->Extensions ->Manage Extensions and delete all Extensions. Close and restart Opera to check loading. As with Widgets, you can also delete them one at a time instead. If you are hesitant about deleting extensions, you can try disabling them first.

Javascript and Plug-ins (includes Flash)

Goto Menu ->Settings ->Preferences ->Advanced Tab ->Content. Uncheck “Enable Javascript“. Hit OK and restart Opera to check loading. If nothing changes, go back and uncheck  “Enable plug-ins“. Hit OK and restart Opera to check loading again. Should Opera load correctly with one or both settings disabled, you may want to make a clean and separate install of Opera using a different directory (not the default directory) and check again.

Opera Advanced Preferences

Reinstalling Opera:

Sometimes it’s best just to start over, especially after several upgrades. To remove Opera, use Add or Remove Programs in Control Panel. This removes the application folder and files, but doesn’t remove the user settings, which are in the folder paths specified in Menu ->Help ->About Opera or in the following directories for a default installation in WinXP:

  • C:\Documents and Settings\username\Application Data\Opera – contains user preferences, session data, the Opera directory, and the user CSS directory.
  • C:\Documents and Settings\username\Local Settings\Application Data\Opera – contains cache, help documents, and the mail directory.

Opera’s plugins are stored in other directories. Use Menu ->Help ->About Opera to identify their locations.

When reinstalling Opera, make sure all other applications are closed.

To remove Opera completely, including all the user settings for WinXP, Vista, and Win7, see How to Uninstall/Remove Opera completely.

To uninstall Opera and save the settings, see uninstall/reinstall Opera browser from Opera’s web site.

Use Stu’s Opera Settings Import & Export Tool  to restore your personal settings after completely removing Opera or installing Opera to a different directory. This tool allows you to easily manage, save, restore or transfer profiles, bookmarks, mail, contacts, sessions, logins, references and more.

Mouse acting Strangely: 

Opera enables mouse gestures by default. This sometimes causes unexpected behavior for users who don’t use this feature. To turn it off, goto Settings ->Preferences ->Advanced Tab ->Shortcuts. At the top of the window, uncheck “Enable Mouse Gestures”. Hit OK to save the setting.

Mouse Gestures window

Cleaning cache, cookies, etc with CCleaner:

CCleaner supports Opera, which makes cleaning up Opera quick and easy. The Opera options are on the applications tab.

CCleaner Opera Options

Speed Tweaks

Cache/History

The cache can be cleaned automatically each time the browser is closed. Goto Menu ->Settings ->Preferences ->Advanced Tab. Select History in the Window and check the “Empty on exit” box. Emptying cache on exit makes Opera start faster, since it doesn’t include the cache. While this setting is open, you may wish to increase the Disk cache setting, especially if you do a lot of off-line browsing or stay on-line for extended periods. Disk cache stores pages locally, increasing browsing speed by eliminating the need to download them again, while also making the pages available off-line.

Opera History Settings

Fraud and Malware Protection

For experienced users aware of the risks, disabling this feature can increase browsing speed. Goto Menu ->Settings ->Preferences ->Advanced Tab ->Security and uncheck Enable Fraud and Malware Protection.

opera security options

Skins

Using the Opera standard or Windows native skin uses less memory, reduces potential compatibility issues and speeds browsing. Skin preferences can be changed from Menu ->Appearance and choosing the Skin tab. Unchecking Enable Special Effects in the Appearance tab may also reduce memory consumption according to this article.

opera appearance settings

References:

Configuring Opera settings from the menu and/or using opera:config:  

Opera’s Settings File Explained

Other useful Opera Articles:

CyberNet News – Opera Tricks & Tips

Opera Browser Wiki – Opera Browser: Tweaks & Settings Guide

How to make Opera consume less memory – Opera memory hog gone

Super User – Opera high memory usage

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04. September 2010 · Comments Off on Manual Creation of RSS 2.0 Feeds for Web Sites · Categories: Web · Tags: Web Development
Last updated on 08/30/2020

rss buttonThis guide shows how to manually create a basic RSS 2.0 feed for web sites quickly and easily. Although other methods exist for adding RSS to web pages, such as various RSS feed software tools, or using feed generation and feed conversion services, there may be limitations, or fee and registration requirements. Tutorials, videos and other instructions for creating RSS feeds are available from multiple web sites, but many can be confusing or contain outdated information. And since the RSS specification changes over time, usually by adding requirements, many software tools become obsolete over time.  With outdated software and RSS specification changes, many videos, tutorials and articles from only a year or two ago, if followed, can create RSS feeds that produce errors when submitted to a RSS validation service. In addition, many on-line feed generation and conversion sites have shut down or have changed from free to paid services. Because of these issues, it’s often desirable to create your own RSS feed. The good news is that creating your own RSS 2.0 feed isn’t terribly difficult.

The following information was tested to ensure that it worked. The method used for this guide was to create a RSS 2.0 feed using an XML file. The only tool needed is a text editor such as notepad, to create the XML file and for adding a line of  code into your HTML web page file(s) to notify browsers of the RSS feed’s existence.

Note: For the code shown below to work correctly, it’s better to type the code rather than copy and paste it. Quotation marks, apostrophes and other characters are sometimes changed by the copy and paste process and become unrecognizable by browsers and other programs although the changes are not always apparent to the eye.
______________________________________________________________________________

Requirements for RSS 2.0

A feed file is a specially formatted XML file made up of elements and sub-elements, which are either declarations or tags. RSS requires only a few elements, but has many optional ones, so feed files can range from simple to complex. For this guide, the declarations and tags for the RSS XML feed file are grouped below into three categories: (1) required,  (2) optional (3) nice to have. As of this posting, RSS 2.0 feeds are more likely to validate and to be accepted by feed directories when ALL the elements for the three categories are included.

Required elements:

  • The XML declaration – This defines the XML version and character encoding (XML version 1.0 and UTF-8 encoding used for this guide).
  • RSS declaration – Defines the RSS version (2.0 used for this guide).
  • channel – The name of the web site. There must be a least one item (web page file/article) within the channel element.
    • title – Title of the channel element.
    • link – Link of the channel element.
    • description – Description of the channel element.
    • item – One for each article or web page file that makes up the web site. Must have at least one item.
      • title – Title of the item element.
      • link – Link of the item element.
      • description – Description of the item element.
  • Closing tags

Optional elements. Through testing, it was discovered that if the following elements are missing in the XML feed file, errors will result when the feed is validated using the W3C Feed Validator:

  • atom:link – Identifies the feed’s URL. Used in the channel element.  Makes the feed more portable, self-contained, and easier to cache. See workbench.org for more information.
  • guid – Globally Unique Identifier. A string that identifies each item element as unique. It has no rules for syntax. Used for each item element.

Nice to have. These elements are not required, but they are useful and almost always included in RSS feeds:

  • language – Identifies the language in the document. Often a requirement for submission to RSS directories.  Used in the channel element.
  • image An image to represent the channel in the channel element. Default size values are 88 for width and 31 for height. Max values are 144 for width and 400 for height.
    • url – Required if using the image element. URL of an image in png, gif, or jpeg format.
    • title – Required if using the image element. Describes the image. Identical to the channel’s title element.  Used for the ALT attribute in HTML rendering.
    • link – Required if using the image element. Link for the image. Identical to the channel’s link element.
    • width – Optional but recommended. Width of image in pixels. If omitted, image width is assumed to be 88.
    • height – Optional but recommended. Height of image in pixels. If omitted, image height is assumed to be 31.
    • description – Optional. Description of image used for HTML rendering.
  • pubDate – Date the item was published. If a future date is used, an aggregator may not display that item until that date.

W3C advises that because RSS is XML, keep in mind that:

  • All elements must have a closing tag
  • Elements are case sensitive
  • Elements must be properly nested
  • Attribute values must always be quoted

Putting all the above information together, below are the steps to create a working RSS 2.0 XML file that can be customized for a web site.

Note: For the code shown below to work correctly, it’s often better to type it yourself rather than copy and paste it. Often, characters are changed by the copy-paste process and become unrecognizable by applications using the code; even though the changes are not apparent to the eye.

______________________________________________________________________________

Steps to Create a RSS 2.0 Feed

  1. Use a Text Editor to Create the XML Feed File

    1. Click feedxml to open the editable XML feed file in your browser or right click it and download it to your computer.
    2. Use a text editor to open the downloaded file or cut and paste the text from the browser page into your text editor.
    3. Customize the file as required for your web site.
    4. Save the feed file as feed.xml
  2. Add Code for RSS detection to your Web Page(s)

    1. To make the RSS feed detectable in web browsers, customize the code below and paste it between the <head> </head> section of the web page(s) you wish to be detectable and then save the changed file:
      <link rel=”alternate” type=”application/rss+xml” href=”https://www.yoursite/feed.xml” title=”Your title”>

    2. Add a RSS feed button to your web page(s) such as those from hongkiat.com.  Be sure to link the RSS feed button to the XML feed file.  Below is an example using a graphic file named feedicon.png:
      <a href=”https://yoursite.com/feed.xml”><img style=”border: 0px solid ; width: 28px; height: 28px;” alt=”feed icon” src=”feedicon.png” />
  3. Upload the XML feed file, modified HTML web page(s), feed image, and the RSS feed button graphic to your server

  4. Validate and publish your RSS Feed

    1. Use W3C to validate your feed either by direct input (cut and paste) or using your feed’s URL (https://yoursite.com/feed.xml). The RSS Advisory Board also provides a feed validation service. The validation process identifies errors and suggests corrections. Make corrections as needed until your feed is validated without errors.
    2. Submit your feed to feed directories to get more traffic. Many are free. A recent listing and review of RSS directories can be found at masternewmedia.org.
  5. All Done.

______________________________________________________________________________

References and Further Info:

XML RSS feeds with Node.js

W3C Shools – RSS Tutorial

RSS Advisory Board

Xul RSS tutorial

RSS 2.0 at Harvard Law

More »

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